Don't wrap INET None values

For Psycopg3 we wrap INET values as strings. This broke the handling of
None values as it converted them to the invalid string "None". Now we
simply pass None values as-is since all Psycopg versions know what to do
with them,

Fixes #128

Author: jimfunk

netfields/fields.py

@@ -91,9 +91,10 @@ def get_prep_value(self, value):
         return str(self.to_python(value))
 
     def get_db_prep_value(self, value, connection, prepared=False):
-        # Django <= 1.8, ArrayField does not pass model to the base_field so we have to check for existance
-        model = getattr(self, 'model', None)
-        if model is None or model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
+        if value is None:
+            return None
+
+        if self.model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
             is_array_field = True
         else:
             is_array_field = False
@@ -205,9 +206,10 @@ def get_prep_value(self, value):
         return str(self.to_python(value))
 
     def get_db_prep_value(self, value, connection, prepared=False):
-        # Django <= 1.8, ArrayField does not pass model to the base_field so we have to check for existance
-        model = getattr(self, 'model', None)
-        if model is None or model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
+        if value is None:
+            return None
+
+        if self.model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
             is_array_field = True
         else:
             is_array_field = False
@@ -256,9 +258,10 @@ def get_prep_value(self, value):
         return str(self.to_python(value))
 
     def get_db_prep_value(self, value, connection, prepared=False):
-        # Django <= 1.8, ArrayField does not pass model to the base_field, so we have to check for existence
-        model = getattr(self, 'model', None)
-        if model is None or model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
+        if value is None:
+            return None
+
+        if self.model._meta.get_field(self.name).get_internal_type() == 'ArrayField':
             is_array_field = True
         else:
             is_array_field = False

test/tests/test_sql_fields.py

@@ -676,6 +676,9 @@ def test_save_single_item(self):
     def test_save_multiple_items(self):
         InetArrayTestModel(field=['10.1.1.1', '10.1.1.2']).save()
 
+    def test_save_with_null_item(self):
+        InetArrayTestModel(field=['10.1.1.1', None]).save()
+
     def test_retrieves_ipv4_ipinterface_type(self):
         instance = InetArrayTestModel(field=['10.1.1.1/24'])
         instance.save()
@@ -694,6 +697,9 @@ def test_save_single_item(self):
     def test_save_multiple_items(self):
         CidrArrayTestModel(field=['10.1.1.0/24', '10.1.2.0/24']).save()
 
+    def test_save_with_null_item(self):
+        CidrArrayTestModel(field=['10.1.1.0/24', None]).save()
+
     def test_retrieves_ipv4_ipnetwork_type(self):
         instance = CidrArrayTestModel(field=['10.1.1.0/24'])
         instance.save()
@@ -712,6 +718,9 @@ def test_save_single_item(self):
     def test_save_multiple_items(self):
         MACArrayTestModel(field=['00:aa:2b:c3:dd:44', '00:aa:2b:c3:dd:45']).save()
 
+    def test_save_with_null_item(self):
+        MACArrayTestModel(field=['00:aa:2b:c3:dd:44', None]).save()
+
     def test_retrieves_eui_type(self):
         instance = MACArrayTestModel(field=['00:aa:2b:c3:dd:44'])
         instance.save()
@@ -730,6 +739,9 @@ def test_save_single_item(self):
     def test_save_multiple_items(self):
         MAC8ArrayTestModel(field=['00:aa:2b:c3:dd:44:55:ff', '00:aa:2b:c3:dd:45:7e:6b']).save()
 
+    def test_save_with_null_item(self):
+        MAC8ArrayTestModel(field=['00:aa:2b:c3:dd:44:55:ff', None]).save()
+
     def test_retrieves_eui_type(self):
         instance = MAC8ArrayTestModel(field=['00:aa:2b:c3:dd:44:55:67'])
         instance.save()